Neutron Therapy - an historical perspective

Sir James Chadwick discovered the neutron in 1932. Just six years later, Dr. Robert Stone began clinical trials treating cancer with neutrons produced by E.O. Lawrence's cyclotron in Berkeley,California. These trials were terminated because the cyclotron was needed for the war effort in World War II.
Clinical research began again in 1965 when Dr Mary Catterall at the Hammersmith Hospital in London began irradiating patients with neutron beams. By 1969, it was clear that for certain tumours, better local control could be achieved using neutron irradiation. Encouraged by these results, the M.D. Anderson Hospital and Tumor Institute in Houston, the Naval Research Laboratory in Washington, D.C., and the University of Washington in Seattle began neutron therapy research. They started treating patients in the early 1970s.

In contrast, UK medicine was slower to be convinced. In 1973 the MRC (Medical Research Council) approved plans for a cyclotron in Edinburgh to be used to attempt to replicate the Hammersmith results. In March 1977, the first patient was treated using the fixed horizontal beam. Two years later the first patient was treated with an iso-centric beam. For reasons which are not obvious, the treatment protocol adopted in Edinburgh was different from the one used successfully in Hammersmith. The Edinburgh results were poor and led, in 1981, to the discontinuation of the neutron therapy programme. There were still, however, some very convincing results for salivary gland tumours and so it was agreed, with significant financial and other support from Mr Joseph Douglas, a philanthropist living in North West England, to build a new machine at Clatterbridge. Clatterbridge had a well-established cancer centre and seemed, save only for its slight geographical remoteness, ideal for the experiment. The new centre opened in 1984. Some 400 patients were treated but, sadly, side effects were bad for some of these - especially those being treated for tumours close to the rectum.
In parallel with this, there was an initiative, supported by a soft Exchequer loan, to build a new facility at St Thomas' Hospital in London. In a heady mixture of medical politics, adverse media coverage and 'interesting' times in national politics, the loan for the St Thomas' cyclotron was withdrawn and reverted to the Treasury. The Clatterbridge cyclotron ceased to treat neutron patients and this aspect of radiotherapy which was largely pioneered in the UK ended there. There is much more to this story than a brief note on a website can tell. The fall out from the bad news story in the UK did affect neutron therapy worldwide.

Some of it was doing very well. Mainly in the USA.

During the 1970s a Neutron Therapy Facility was built at Fermilab. It used a beam from the large existing physics-based facility. The beam had some disadvantages compared to modern standards - it was 'fixed' and not easily accessible for patients. But great ingenuity and dedication enabled it to start treatment in 1976 after measurements of neutron beam characteristics and dose distributions were completed. The National Cancer Institute funded the operation of the facility from June 1975 to October 1985. Cliniical trials were conducted to determine the appropriateness of using neutrons to treat various types of cancers. One significant finding from these multi-institutional trials was that only neutron beams produced by protons or deuterons with energies greater than about 50 MeV could produce tumour control with side effects no worse than low LET radiation. For this reason facilities which had performed clinical trials using relatively low energy beams either stopped treating patients or upgraded their accelerators to a higher energy.
In Seattle, at the University of Washington, [yet to be completed]